Distribution apparatus for being interposed in CATV transmission cables come in different types due to the needs to provide input and output cable connecting portions in different positions and also to provide various numbers of taps. To meet these needs, multi-tap distribution apparatuses for general purpose use have been proposed whose internal mechanisms are composed of a plurality of modules. In one type of such general-purpose distribution apparatuses, a mother board with a current transmission circuit and a branch circuit board are designed in modules that can be assembled in different ways to suit particular applications.
CATV transmission cables carry not only television signals, control signals, and other high-frequency signals but also currents for operating main line amplifiers. For this reason, the above-mentioned type of distribution apparatuses are designed to transmit currents therethrough. Currents should not be carried through the branch circuit or the distribution circuit of this type of apparatuses. To avoid this, these distributors have a dedicated circuit provided in a mother board especially for current transmission and connect the input and output cable connecting portions via the dedicated circuit. Generally, these apparatuses employ an insertion type connecting structure to connect the mother board with the transmission cables, which are directly coupled to the input and output cable connecting portions.
Although only currents of low amperage are passed to each tap in this type of apparatuses, the cable connecting portions carry the same maximum currents as the main line does. Therefore, the transmission losses between the input and output cable connecting portions must be reduced and any adverse effect on the characteristics of the electromagnetic waves must be also minimized.
However, the aforementioned insertion type connecting structure causes not only transmission losses easily but also over-heating if a current of high amperage is carried therethrough, so that the heat may affect the characteristics of the circuits mounted on the mother board.